Infrared proximity sensor packages are known in the art. One example of such a device is the AVAGO TECHNOLOGIES™ HSDL-9100 analog-output reflective sensor package, which contains an integrated high efficiency infrared emitter and a detector or photodiode housed in a small form factor surface mount device (SMD) package. In the HSDL-9100 proximity sensor package, as in many other proximity sensor packages manufactured by companies other than AVAGO TECHNOLOGIES™ such as SHARP™, ROHM™ and VISHAY™, infrared transmitter dice must be placed in very close proximity to infrared receiver dice (i.e., mere millimeters apart in the same package). Transmitted or received Infrared light rays tend to bounce around or reflect internally within such packages, resulting in undesired infrared signal crosstalk occurring in respect of both the transmitter dice and the receiver dice. As the demand for ever smaller proximity sensor packages increases, the problem of eliminating or reducing such infrared signal crosstalk becomes more severe.
The HSDL-9100 package comprises a stainless steel housing that requires over 30 separate steps to manufacture, including relatively intricate metal folding steps. Other types of housings that have been employed in prior art infrared proximity sensors include metal foil and metal-plated or coated plastics. Metal foil housings feature numerous seams and thus have a tendency to leak undesired internally-reflected infrared signals through or around such seams. Metal-plated plastic housings are difficult and expensive to manufacture, and in general do not feature very high levels of infrared signal crosstalk isolation between the transmitter and receiver portions thereof. Further exacerbating the foregoing problems is the distinct tendency of infrared radiation to pass substantially or barely unattenuated through many different materials, such as printed circuit boards, many plastics and polymers, and even thin ceramic materials.
What is needed is a housing for an infrared proximity sensor package that features reduced infrared signal crosstalk and that is inexpensive and easy to manufacture.